On June 14, 1972, a large area of disturbed weather was identified over Mexico’s Yucatán Peninsula. It became a tropical depression that day while drifting eastward into the far northern Caribbean Sea. On 16 June after turning to the north, the depression became the first tropical storm of the 1972 hurricane season and was named Agnes. It was a very large storm, extending over 3215 km (2,000 mi) outward from its center. Agnes developed into a hurricane on 17 June over the southeastern Gulf of Mexico. The hurricane did not strengthen any higher than Category 1 status, peaking at 137 km/h (85 mph), before making landfall on June 19 on Florida’s Panhandle near Cape San Blas with winds of 119 km/h (74 mph). Storm tides 1.5-1.8 m (5-6 ft) above normal caused erosion and flooding along the coast of the Panhandle that resulted in $12 million (1972 USD) in property damage. Fifteen tornadoes spawned by the hurricane also produced damage in the state.

A satellite image of the remnants of Hurricane Agnes. Source: NOAA

After its Florida landfall, the hurricane turned to the northeast and began weakening. For much of its travel across the southeastern United States, Agnes was a tropical depression. On 21 June, while over North Carolina, the storm reintensified into a tropical storm due to its interaction with an approaching trough. Tropical storm Agnes approached hurricane intensity after moving off the Virginia coast into the Atlantic Ocean, however it did not reach hurricane status as it had been so severely weakened previously. On 22 June, the storm made its final landfall near New York City, NY. The next day the remnants of Tropical Storm Agnes merged with the afore mentioned low-pressure system over Connecticut, creating rainfall as it passed over the northeastern United States until 25 June.

Tropical Depression Agnes dumped less than 100 mm (4 in) of rain while moving over the state of Georgia. The interaction with the low over North Carolina, however, caused a sharp increase in rainfall. The system dropped about 150-250 mm (6-10 in) of rain over that state with much higher amounts farther north. Between 250-350 mm (10-14 in) fell over a broad area that included Virginia, Maryland, Pennsylvania and New York. The highest amount of occurred in Western Schuylkill County, Pennsylvania where 480 mm (19 in) was measured. This large amount of rain caused severe flooding throughout the region. The worst urban flooding occurred in Elmira, New York and Wilkes-Barre, Pennsylvania. In Elmira, 20,000 people were forced out of their homes by rising waters, and downstream flooding caused a dike to be breached in Wilkes-Barre resulting in the near destruction of the entire town. In the Pennsylvania capital of Harrisburg, the governor’s mansion was submerged in floodwaters. As rivers crested to record levels, homes, businesses, factories, bridges and other infrastructure saw very significant damage. Freshwater flooded Chesapeake Bay killing large numbers of freshwater intolerant species causing losses for the local seafood industry, as product that would normally be harvested, recovered.

Hurricane Agnes took 130 lives along its path, 113 of which were a direct result of flooding. Total damages from Hurricane Agnes amounted to about $2.1 billion (1972 USD) making it the most costly U.S. hurricane at the time. The vast majority of the damage was due to flooding, especially in the state of Pennsylvania, where $2 billion in damage occurred. An additional $700,000 (1972 USD) of damage occurred in New York, and the Category 1 status of the storm as it passed over Florida largely spared the state. Hurricane Agnes is a good example of how destructive weak storms can be.

Fast Facts:

Hurricane Agnes was the first Category 1 hurricane in the Atlantic basin to have its name retired. As of the close of the 2010 season, it is one of only five such hurricanes. Hurricanes Klaus (1990), Cesar (1996), Stan (2005) and Noel (2007), which were also Category 1 hurricanes whose names have been retired by the World Meteorological Organization due to their deadly or otherwise destructive impacts.

Hurricane Agnes devastated the ailing railroads in the Northeast as floodwaters destroyed many rail lines. The event is one of the factors that led to the formation of the Conrail rail system, a federally funded railway that replaced the damaged and bankrupt lines that existed before the hurricane.